The present invention relates to a drive control apparatus that drives a control target by a two-degree-of-freedom system control with a combination of feed-forward control and feed-back control.
There is a known method of driving a control target along a target trajectory, in which feed-forward control and feed-back control are combined to enhance followability and responsiveness. However, this method involves the following problems: Since a reverse model of a transfer function of the control target is required to be performed by a target trajectory generation model, designing may be difficult in case of a complicated control target. Also, an unstable zero may be generated depending on a setting of a sample time in digitization. Further, generation of a nonlinear target trajectory may not be performed.
Accordingly, a control method of a two-degree-of-freedom system is usually used. In this method, an operation amount command is configured to be a simple feed-forward command, and feed-back correction of the feed-forward command is performed based on an actual movement amount (control amount) of the control target.
That is, a difference between a target movement amount and an actual movement amount, which is caused in case of driving a control target based only on a feed-forward operation amount, is compensated by a feed-back compensation amount as an operation amount by feed-back control. This will lead to an improved control performance.